add latest visited branch as a fallback in magit-guess-branch
Don't use find-if
fix for branches starting with 'to'
magit-remote-branch-for: deal with branch.b.remote being undefined

If branch.b.remote is undefined return nil just as we already do if
branch.b.merge is undefined.  We could instead default to the local
repository (".") but git itself also does not do that.
magit-remote-string: check whether remote-branch is non-nil

Otherwise return nil.  Previously this attempted to propertize nil.
Merge commit '9c6f2d511f8e9d16c474b69ae89176cabfa331b2' into tarsius/remote-or-merge
Merge commit '6bdb9db752bde665bce8f628380d206047047022' into kidd/master
Merge branch 'tarsius/remote-or-merge'
Merge branch 'kidd/master'